1. Field
The invention is in the field of pop-up irrigation sprinklers which allow for manual adjustment of the angular relationship of the riser and housing.
2. State of the Art
Irrigation systems, such as turf watering systems, are used extensively, particularly in arid and semiarid areas of the world, such as the western portion of the United States. The typical modem turf watering system consists of a plurality of pop-up sprinklers spaced according to the range of the sprinklers so as to cover the entire turf area. Individual sprinklers are fed by underground water pipes connected to a water supply source through electrically operated valves and retract during periods of non-watering so as not to be obstructions to the normal daily activities. The sprinklers are typically organized into groups or zones such that several individual sprinklers in a particular area of the turf are controlled by a single valve, with several separately controlled groups or zones required to cover the entire turf area. Typically, only one zone is watered at a time to ensure sufficient pressure to operate the sprinklers in the zone.
The direction of water spray from such sprinklers is obviously important so as to provide water where needed, but not to those areas where not needed or wanted, such as to roads, parking lots, sidewalks, and against buildings. This aiming of the spray is typically accomplished by turning the sprinkler housing with respect to the water supply pipe to which it is attached, by turning the water supply pipe with respect to an up stream connection of such pipe, or a combination of both. However, such turning can loosen the housing or supply pipe causing it to leak. Some pop-up sprinklers are available were the riser tube which rises from the sprinkler housing is rotatable with respect to the housing to aim the spray of water where needed. This rotatability can be accomplished in various ways. One way is to provide a lower gear or flange having fine teeth about the outer perimeter thereof as part of the riser tube and a plurality of mating internally directed tabs such as in the form of splines which extend longitudinally along the length of the housing in which the riser longitudinally slides to engage such teeth. As the riser tube rises and falls during use, the orientation of the spray nozzle attached at the upper end thereof is maintained due to the engagement of the teeth with the splines, the inwardly directed edges of the splines typically being pointed to fit in the grooves between the teeth. The riser tube may be forcibly rotated, slightly flexing the splines, the teeth, or both, to skip the teeth past the splines to allow angular repositioning of the riser tube with respect to the housing to thereby reposition the direction of spray from the spray nozzle. This process wears out the teeth and/or the splines over a relatively short period of time resulting in loss of the rotationally locking function. A repositioning system for pop-up sprinklers as described, as well as other specific embodiments are disclosed in U.S. Pat. No. 4,220,283 issued to Citron, which disclosure is hereby incorporated by reference.
The invention comprises a pop-up sprinkler of the type having a housing with a lower end for connection to a water supply with an opening therethrough for admitting water, and an opening through an upper end thereof for closely passing a riser tube. A riser tube is slidably and rotatably engaged within the housing with an upper end thereof which extends through an opening through the upper end thereof, with a spray nozzle mounted thereto. A compression spring engages the upper portion of the housing and the a lower portion of the riser tube to maintain the riser tube in a retracted position until water is admitted through the opening in the lower portion of the housing, acting against a lower, radially outwardly extending annular flange of the riser tube. A plurality of internally directed splines of the housing extend longitudinally therethrough, having respective sharpened, inwardly directed edges which engage radially outwardly extending teeth peripherally disposed about the flange of the riser tube, forming a gear. A plurality of inwardly radially directed slots in the flange allow the flange to flex slightly so as to minimize the shearing and other stresses between the splines and teeth during forcible changes in rotational orientation therebetween during re-aiming of the riser tube and nozzle. This dramatically increases the wear life of the gear teeth and the splines over non-slotted gear designs. Preferably, three or six equally spaced splines are used with four equally spaced slots such that all of the splines do not simultaneously engage a slot, which condition would possibly create more rotational vibration and movement during use than desired.